1. Technical Field
The present invention relates to a vehicle travel control device that controls a following travel to a vehicle traveling in front of a subject vehicle.
2. Related Art
Up to now, in vehicles such as automobiles, as disclosed in Japanese Unexamined Patent Application Publication No. 2004-322916, a following travel system for following-traveling a preceding vehicle that travels in front of a subject vehicle has been known. In the following travel system to the preceding vehicle, the preceding vehicle is captured by a radar or a camera to automatically control steering, a transmission, an engine and a brake of the subject vehicle. This sort of the following travel system has advantages in cases such as traveling on a road without any lane marker and any lane line on a road surface, and an inter-vehicle distance between the subject vehicle and the preceding vehicle being decreased during traveling at a low speed such as a traffic congestion to limit a forward field of view, thereby making it difficult to recognize the lane lines.
In the following travel system described above, generally, a rear area of the preceding vehicle is observed to calculate a travel locus, and a center position of the subject vehicle in a vehicle width direction is controlled to coincide with the calculated travel locus. However, when another vehicle cuts in between the subject vehicle and the preceding vehicle, the rear area of the preceding vehicle which can be detected from the subject vehicle is reduced, resulting in a possibility that the center position of the preceding vehicle in the vehicle width direction is recognized with an offset from an original position. As a result, the subject vehicle may travel following the preceding vehicle with a deviation from the preceding vehicle by the amount of offset recognition.